Electronic filters and their controls desirably yield high quality signals, especially in medical signal acquisition where signals are in the millivolt level, such as surface electrocardiogram (ECG) and intra-cardiac electrogram (ICEG) signals. Known signal processing systems use an application-specific scheme of filters while sacrificing flexibility and user interface area for high quality signal management. Also, known filters are typically not adaptive (they fail to filter noise if the noise shifts out of a band stop region). Signal acquisition systems need to process a variety of noise sources that are variable in amplitude and frequency in order to provide a clean signal from an input source, such as a patient in the presence of patient movement noise, power line electrical noise and electrical and magnetic noise from other medical instruments in hospitals.
For example, known ECG signal acquisition systems typically use several large and cumbersome low-pass filter, notch filter, and high-pass filter networks implemented with operational amplifiers. Further, known signal acquisition filtering schemes are typically not adaptive and are sensitive to noise if the line frequency shifts from 60 Hz to 60.1 Hz. Further, settings of known filter systems are typically complicated and difficult to optimize. For instance, surround sound users are often unable to optimize parametric equalizers because of interface complexity. In addition, current filter systems in medical devices typically have no sub-frequency band control, such as different sub-frequency bands like 50-60 Hz or 200-250 Hz, in an encompassing signal bandwidth (0-2000 Hz). Efficient and correct manual filter control and adjustment needs extensive experience and knowledge, which increases work complexity for medical users. A system according to invention principles addresses these deficiencies and related problems.